Question

我想用另一个表中的数据更新表

表1 OverseasOperation和表2为ForecastTotal

我使用了这个命令但它只复制了第一个值

Update ForecastTotal 
Set OVERSEASVol = Sales 
From OverseasOperation

结果是Sales = OVERSEASVol

中的第一个值

结果是

但我想得到像这样的表

出了什么问题？

注意：我想更新不插入，并且不想创建条件，因为我想要复制所有数据

Answer 1

最通用的方法是使用相关子查询：

Update ForecastTotal
    Set OVERSEASVol = (select Sales
                       from OverseasOperation oo
                       where oo.?? = ForecastTotal.??
                      );

??用于连接条件。目前还不清楚哪些列用于连接两个表。

注意：许多数据库支持在update语句中连接表的某种方法。这些方法往往依赖于数据库。

Answer 2

试试吧

;with ForecastTotal_Temp
as
(
select ForecastTotal.OVERSEASVol as OVERSEASVol, row_number() over (order by OVERSEASVol) as rownum
from ForecastTotal
)

update ForecastTotal_Temp
set OVERSEASVol = (
                    select sub.Sales 
                    from (select OverseasOperation.Sales AS Sales, row_number() over(order by Sales ) as rnum from OverseasOperation) sub 
                    where sub.rnum=ForecastTotal_Temp.rownum
                  )

Answer 3

假设表共享一个唯一的公共密钥（称之为ukey），那么

update ForecastTotal
   set sales = OverseasOperation.Sales
from ForecastTotal
join OverseasOperation on ForecastTotal.ukey = OverseasOperation.ukey

如果OverSeasOperation有多次出现来自ForecastTotal的主键，则必须对销售额进行求和，在主键上分组，并将wiill用作连接上的第二个表，如下所示

update ForecastTotal
   set sales = oo.Sales
from ForecastTotal
join 
( 
    select ukey, sum(Sales) sales
    from OverseasOperation
    group by ukey
) oo
on ForecastTotal.ukey = oo.ukey

此外，如果您希望通过添加OverseasOperation的销售额来更新ForecastTotal销售额，请更改

中的设置

set sales = OverseasOperation.Sales

到

set sales = sales + OverseasOperation.Sales

如何从SQL Server中的另一个表更新一个表？

3 个答案: